Senior Java Developer

Experience - 6+ years

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- Java (modern LTS, 21+) as the primary language deep, current, hands-on expertise is essential.
- Spring Boot 3.x and the wider Spring ecosystem (Spring Web / WebFlux, Spring Security, Spring Data, Spring Cloud); reactive programming with Project Reactor is a strong plus.
- Gradle (Kotlin DSL), version catalogs, multi-repo / composite builds, and CI/CD pipelines (Jenkins, Git-based workflows).
- OpenAPI-first API design with code generation, API linting/governance, and disciplined versioning.
- Relational databases and schema evolution: PostgreSQL, JPA/Hibernate, Flyway migrations, query performance and data modelling.
- Event-driven and asynchronous messaging: Apache Kafka, event/command-driven or CQRS-style architectures (e.g. Axon), and reliable delivery patterns such as the transactional outbox.
- Containerised delivery and cloud-native operations: Docker, orchestration platforms, configuration and secret management (e.g. HashiCorp Vault), 12-factor configuration.
- Observability in production: structured logging, metrics, tracing, dashboards and alerting including how to instrument systems that must never log sensitive data.
- Git and contemporary collaborative development practices (PR-based workflows, code review culture, semantic versioning).

Security and cryptography

- Good working knowledge of industry-standard cryptographic algorithms and primitives — symmetric (AES, 3DES), asymmetric (RSA, ECC), hashing, MAC/CMAC, key derivation and key wrapping — and sound judgement on how, where and when to apply them.
- Practical experience with key management concepts: key hierarchies, LMKs,



transport/zone keys, key blocks (e.g. TR-31), key ceremonies, rotation, custody, key states and lifecycle.
- Hands-on experience integrating with Hardware Security Modules (e.g. Thales payShield, Entrust nShield) and cryptographic interfaces such as PKCS#11 and JCE/JCA.
- PKI and certificate management: X.509, CA hierarchies, CSR/issuance flows, certificate lifecycle and validation; EMV issuer certificate concepts are a strong plus.
- Secure service-to-service communication: TLS/mTLS, keystores and truststores, authentication/authorisation and policy enforcement at the gateway.
- Secure development mindset: threat modelling, least privilege, secure defaults, secrets handling, and an instinct for never exposing key material, PANs, cryptograms or tokens in logs, traces or errors.
- Familiarity with payments domain standards and regulatory/compliance drivers (PCI DSS / PCI PIN / PCI P2PE, EMV, ISO 8583) is highly desirable.

Ways of working

- Expert critical-thinking and problem-solving skills; able to reason from first principles about unfamiliar, high-stakes systems.
- Highly motivated and proactive about the success of the team and the product, not just individual deliverables.
- High-energy, detail-oriented and able to handle multiple high-priority demands while driving consistent, predictable results.
- Excellent written and verbal communication; can explain complex cryptographic and architectural concepts to both specialist and non-specialist audiences.
- Comfortable working in a globally distributed team, and a demonstrated willingness to mentor, document and share knowledge.

📌 Senior Java Developer (HSM Cyptograpgy) (Pune)
🏢 Opus Technologies
📍 Pune